Grades inside a Prime course site can be viewed by clicking on the Report tab and running a Report:
Grades may not be available until the faculty member releases them.
Grades may be placed into Prime by your instructor for items/activity on Prime — for example, exams using Quizzes/Assessments, papers submitted to a DropBox — or activities/items outside of Prime — attendance, class participation, clinical activity, etc.
Note that the "official" course grade is uploaded by the instructor into Banner. To view that grade, go to myDownstate, log into Banner Self-Service and click on the folder icon located inside the Banner Self-Service Channel.